Photovoltaic cells, commonly known as solar cells, are well known devices for direct conversion of solar radiation into electrical energy. Generally, solar cells are fabricated on a semiconductor wafer or substrate using semiconductor processing techniques to form a p-n junction near a surface of the substrate. Solar radiation impinging on the surface of the substrate creates electron and hole pairs in the bulk of the substrate, which migrate to p-doped and n-doped regions in the substrate, thereby generating a voltage differential between the doped regions. The doped regions are coupled to metal contacts on the solar cell to direct an electrical current from the cell to an external circuit coupled thereto.
Typically, the surface of the solar cell to receive radiation is textured and/or coated with a layer or coating of an anti-reflective material to decrease the reflection of light, thereby increasing the efficiency of the solar cell. The fabrication of such solar cells, in particular the formation of the p-n junction and contacts thereto, involves a number of complicated process steps including the deposition, doping and etching of many different layers of material. These process steps are performed or carried out with low variation tolerances using many different processing tools under controlled environmental conditions.
Accordingly, there is a need for a simplified process for fabricating solar cells that reduces the number of separate steps needed, thereby reducing the time and cost of fabricating solar cells. It is further desirable that the method eliminates entirely the need for one or more processing tools, thereby further reducing the cost of fabricating solar cells.